LAUSR

Abstract Rationale: IgG4-related disease (IgG4-RD) is a systemic disease that can involve various organs and is characterized by the infiltrations of IgG4-positive plasma cells and lymphocytes, fibrosis, and elevated serum IgG4 levels. IgG4-related sclerosing cholangitis (IgG4-RSC) is a subtype of IgG4-RD. No certain relationship between IgG4-RSC and cholangiocarcinoma has been established as yet, and there have been few reports of the simultaneous diagnosis of IgG4-RSC and cholangiocarcinoma. Patient concerns: A 76-year-old male visited our gastroenterology department due to the recent occurrence of pruritus and jaundice. Diagnosis: Computed tomography (CT) scan showed ductal wall swelling and enhancement from both intrahepatic duct confluence to the common bile duct, upper biliary dilatation, and accompanying autoimmune pancreatitis (a sub type of IgG4-RD). Biopsy of the distal common bile duct by endoscopic retrograde cholangiopancreatography (ERCP) resulted in a diagnosis of IgG4-RSC. Subsequently, adenocarcinoma was identified by repeated cytology of bile juice. Finally, Klatskin tumor type IIIA and IgG4-RSC were concurrently diagnosed. Interventions: IgG4-RSC was treated with steroid and Klatskin tumors by gemcitabine + cisplatin chemotherapy. Outcomes: The jaundice had improved and CT showed substantial improvement of the intrahepatic duct dilatation. Lessons: IgG4-RSC and cholangiocarcinoma are easily confused, but their treatments are quite different, and thus, care must be taken during diagnosis. Furthermore, these 2 diseases may co-exist. Therefore, even if IgG4-RSC is diagnosed first, the possibility of accompanying cholangiocarcinoma should be thoroughly investigated.